Recovery and cooling system for drycleaners



Feb. 7, 1967 A. E. MCCLEAD RECOVERY AND COOLING SYSTEM FOR DRYCLEANERSFiled May 15, 1964 //V l EN 709 A. 5. Ma (1540 *CYM A TTORNEV UnitedStates Patent 3,302,300 RECOVERY AND COOLING SYSTEM FOR DRYCLEANERSAlpheus E. McClead, RD. 1, Franklin Township,

Mansfield, Ohio, assignor to Westinghouse Electric Corporation, EastPittsburgh, Pa., a corporation of Pennsylvania Filed May 15, 1964. Ser.No. 367,703 3 Claims. (Cl. 3475) This invention relates to the operationof machines handling liquid solvents used for the cleaning of fabricsand particularly to the recovery of the solvents after the fabrics havebeen subjected to the solvents in liquid form. These solvents aregenerally of a volatile nature so that any of the liquid left in thefabrics after a cleaning operation may be removed therefrom bysubjecting the fabrics to a stream of heated air. Since a considerableamount of solvent is thus removed from the fabrics it becomes a matterof economy to recover this so means is provided to make the recovery bymoving the air-vapor stream away from the fabrics to another point wherethe vapor is condensed and returned to the main body of solvent. Thisoperation takes place as a definite step in the drycleaning process.

It is an object of the present invention to render the alternatingprocesses of volatilization and condensation as rapid and as complete aspossible whereby economy in the operation of the device may bepracticed. To meet this object the physical embodiment of thedrycleaning device has been carefully fashioned to take advantage ofnatural laws of the movements of gases and the factors controlling thecondensation of gases to liquids. In this recovery process the solventis alternately volatilized by hot air and thereafter moved to anotherlocation where it is condensed by contact with cold surfaces, such asthe main body of solvent in its storage tank and enlarged surfaces ofducts and passageways as well as coils carrying a coolant. The ductsconveying the solvent laden air are made as large as possible to renderthe movement of the air-vapor stream as slow as possible wherebycondensation on the cooled surfaces thereof will take place ascompletely as possilbe. All surfaces where condensation takes place areconstructed and arranged to move the condensed solvent back to the mainbody of solvent by gravity.

Another object of the invention is the provision of means to change thenature of the moving stream radically at different points in itscircuit, being clear air for one part of its movement and air heavilyladen with gaseous solvent for another part of such movement.

The perchlorethylene or other solvent used for drycleaning operation isvolatile and expensive and must be conserved for this reason as well asto avoid contamination of the atmosphere in and about the location whereit is used. Added to this, time is a factor since the number ofdrycleaning operations carried out per unit of time determines thesuccess of the establishment. The solution to a gain in efficiencyresides generally in utilizing all cooled areas possible for bringingthe airvapor mixture to the condensing temperature of theperchlorethylene or solvent vapor in such manner that the condensationcan be mechanically mingled with the liquid in the least possibledistance and effort. Moving of the cooling area down and the heatingarea up uses the natural tendency of cool vapor to sink and hot vapor torise while rendering the piping runs shorter. In accordance with thisinvention there is better power utilization since the cooler unit isused totally, when and where needed. The simple arrangement ofcomponents herein set forth while not producing any spec- "ice tacularresults does provide a substantial gain in efficiency.

Another feature of this invention resides in the construction of thecirculation path, that portion of the gaseous stream carrying theair-vapor mixture being tightly confined to prevent escape into theatmosphere of the location whereas the other part carrying only air maybe in communia'ction with the exterior of the machine so that an extraamount of air may be taken in during operation.

Cooling coils in the air-vapor stream are designed to utilize lowvelocity air at the point where liquid solvent runs 01f and drops backinto the tank so that movement of the liquid will not be impeded. Themovement of the heated air delivered to the tub shall be comparativelyhigh velocity to produce rapid volatilization of any remaining solvent.The air heater is so located that the air moves upwardly toward theinlet to the tub and the solvent condensing means including the storagetank and the condenser are located below the heater and the tub. Thecondenser is located substantially within the storage tank and a singlehelix of cooling coils serves both to cool the main body of liquidsolvent and to act as a condenser in the final reach of the air-vaporstream before it moves upwardly to the heater.

The drawings consist of a single sheet having three figures, as follows:

FIGURE 1 is a front view, partly in vertical section with most of thecabinet broken away to show schematically the location and spatialarrangement of the various elements of the solvent'recovery system;

FIG. 2 is a side view, partly in vertical section with most of thecabinet broken away to show schematically the location and spatialarrangement of the various elements of the solvent recovery system; and

FIG. 3 is a sectional view taken on the line III-III of FIG. 1 showingthe shape of the duct and the cooler coils substantially constituting acondenser and loading from the top of the solvent storage tank to theheater.

In the drawings the drycleaning apparatus is shown as being housed in acabinet 1. The elements of the recovery system consist of the tub 2, anair-vapor duct 3, a lint trap 4, a blower 5, a duct 6 to carry the vaporladen air to the solvent storage tank 7, a duct 8 to carry the air nowhaving a large percentage of its vapor separated therefrom bycondensation as it moves slowly over the cool solvent in the storagetank 7, from the storage tank to a heater 9, this duct substantiallyconstituting a condenser and, lastly, a duct 10 to carry the heated airto the tub where it acts to vaporize any solvent left in the fabricswhich have been subjected to the solvent in liquid form. The air used tovaporize the remaining solvent in the cleaned fabrics is this heated airfrom the heater 10, mixed with fresh air taken in at the front part ofthe tub, this mixture being self-adjusting and depending on the suctioncreated at this point by the blower 5. It will be seen that after thefabrics in the tub have thus been cleaned by the conventional tumblingaction in the tub, a valve 11 is opened and the liquid solvent is drawnoff through the pipe 12 and run into the storage tank 7, the heated airfrom the heater 9 will act to vaporize any solvent left in the fabricsand this will move in the circuit described. A water cooler, not shown,is provided to circulate cold water through coils 13 and 14 hereinschematically shown, which are submerged in the body of solvent 15 andextend well up into the duct 8. These cooling coils keep the body ofsolvent 15 well below the temperature at which the vapor in the vaporladen air delivered through the duct 6 will condense to its liquid form.The movement of this air-vapor over the top surface of the storedsolvent is comparatively slow so that condensation is substantiallycomplete by the time the stream has reached the duct 8. Since part ofthe cooling coils 13 are located in this duct the coils and the largesurfaced triangular sides of the duct 8 constitute a condenser and thisremoves any solvent vapor left in the stream so that it is substantiallyclear air which becomes heated in the heater 9 and delivered to thefabrics in the tub 2. The duct 8 is made triangular in cross section toprovide ample cooled surfaces and an efficient runway for the liquidsolvent recovered from the air stream leading to the heater 9.

Any water that is recovered by condensation will form as a layer overthe top surface of the stored solvent and may be run off by a U tube 16.

Thus, by taking advantage of the natural tendency for heated air andvapor to move upwardly and cooler air and vapor to move downwardly andto the use of minimum lengths of tubing and all cooling surfaces beingconstructed to deliver condensed vapor to the storage tank, a gain inefficiency is achieved whereby the recovery of solvent is more completeand rapid.

What is claimed is:

1. A solvent recovery system for drycleaners consisting of a combinationof elements including a tub, a lint trap, a blower, a solvent storagetank, a condenser, a heater and ducts interconnecting said elements toprovide a passageway for air and for air laden with solvent vaporthrough said elements in the order set forth, a helix of coils carryinga coolant within said solvent storage tank and projecting into a ductleading from said tank to said heater to constitute a condenser, saidstorage tank being placed under said tub, lint trap and blower wherebysaid duct leading from said blower to said storage tank is orientedvertically to move the air vapor stream downwardly as it changes intemperature from hot to cold, said heater being placed above saidstorage tank and said condenser to move hot air into said tub wherebysaid duct leading from said condenser to said heater is orientedvertically to move the air stream upwardly as it changes in temperaturefrom cold to hot, characterized by the construction of said storage tankand the location of said duct from said blower and the location of saidcondenser whereby the air vapor stream moving over the surface of saidstored solvent moves comparatively slowly over a maximum area thereof.

2. A solvent recovery system for drycleaners consisting of means forheating air for admission to a tub containing solvent cleaned fabrics,fan means for moving solvent laden air from said tub downwardly to astorage tank containing a body of stored solvent, a passageway from saidstorage tank at a point distant from that at which said fan means movessaid solvent laden air into said tank, said passageway leading upwardlyto said air heater, and a helix of cooling coils submerged in said bodyof stored solvent and extending upwardly into said passageway, saidhelix of cooling coils serving to maintain said body of solvent at atemperature below that at which solvent vapor in said stream moved bysaid fan will condense to its liquid state and said helix of coolingcoils extending into said passageway substantially constituting acondenser to condense final traces of solvent vapor in said streambefore said air is reheated for recirculation in said air-vapor stream,characterized by the construction and arrangement of said combination ofmeans to move heated air upwardly and cooling air laden with solventvapor downwardly and further characterized by the construction andarrangement of a closed air-vapor circulation passage from the said tub,through the fan means, over the surface of the cooled body of solventand through the condenser to confine vaporous solvent, and an openpassageway for heated air into said tub for admission of more air asneeded for the recovery process.

3. A solvent recovery system as set forth in claim 2, characterized bythe use of a triangularly shaped passageway substantially constituting acondenser, having an apex at its low point to facilitate the downwardmovement of condensed solvent against the upward movement of airtherein.

References Cited by the Examiner UNITED STATES PATENTS 1,457,768 6/1923Curran. 1,815,938 7/1931 Trogner 164 X 2,019,011 10/1935 Johnson.3,113,445 l2/1963 Williams et al. 3476 X 3,122,908 3/1964 Stanulis etal. 34-77 X 3,221,525 12/1965 Jacobs 34-76 JAMES W. WESTHAVER, PrimaryExaminer. FREDERICK L. MATTESON, JR., Examiner.

C. R. REMKE, Assistant Examiner.

1. A SOLVENT RECOVERY SYSTEM FOR DRYCLEANERS CONSISTING OF A COMBINATIONOF ELEMENTS INCLUDING A TUB, A LINT TRAP, A BLOWER, A SOLVENT STORAGETANK, A CONDENSER, A HEATER AND DUCTS INTERCONNECTING SAID ELEMENTS TOPROVIDE A PASSAGEWAY FOR AIR AND FOR AIR LADEN WITH SOLVENT VAPORTHROUGH SAID ELEMENTS IN THE ORDER SET FORTH, A HELIX OF COILS CARRYINGA COOLANT WITHIN SAID SOLVENT STORAGE TANK AND PROJECTING INTO A DUCTLEADING FROM SAID TANK TO SAID HEATER TO CONSTITUTE A CONDENSER, SAIDSTORAGE TANK BEING PLACED UNDER SAID TUB, LINT TRAP AND BLOWER WHEREBYSAID DUCT LEADING FROM SAID BLOWER TO SAID STORAGE TANK IS ORIENTEDVERTICALLY TO MOVE THE AIR VAPOR STREAM DOWNWARDLY AS IT CHANGES INTEMPERATURE FROM HOT TO COLD, SAID HEATER BEING PLACED ABOVE SAIDSTORAGE TANK AND SAID CONDENSER TO MOVE HOT AIR INTO SAID TUB WHEREBYSAID DUCT LEADING FROM SAID CONDENSER TO SAID HEATER IS ORIENTEDVERTICALLY TO MOVE THE AIR STREAM UPWARDLY AS IT CHANGES IN TEMPERATUREFROM COLD TO HOT, CHARACTERIZED BY THE CONSTRUCTION OF SAID STORAGE TANKAND THE LOCATION OF SAID DUCT FROM SAID BLOWER AND THE LOCATION OF SAIDCONDENSER WHEREBY THE AIR VAPOR STREAM MOVING OVER THE SURFACE OF SAIDSTORED SOLVENT MOVES COMPARATIVELY SLOWLY OVER A MAXIMUM AREA THEREOF.